PT-2026-41657

Name of the Vulnerable Software and Affected Versions Mattermost versions 11.4.x through 11.4.3 Mattermost versions 11.5.x through 11.5.1 Description An issue exists where the burn-on-read reveal endpoint fails to validate the 'X-Requested-With' header. This allows an authenticated channel member...

PT-2026-41639

Name of the Vulnerable Software and Affected Versions Mattermost versions 11.5.0 through 11.5.1 Mattermost versions 10.11.0 through 10.11.13 Mattermost versions 11.4.0 through 11.4.3 Description An authenticated attacker can cause resource exhaustion or denial of service by sending a crafted...

Mattermost 访问控制错误漏洞

Mattermost is an open-source collaboration platform developed by the American company Mattermost. Versions of Mattermost such as 11.5.1 and earlier 11.5.x series, as well as 11.4.3 and earlier 11.4.x series, have a access control vulnerability. This vulnerability stems from the failure to validat...

Mattermost Plugins 安全漏洞

Mattermost Plugins is a plugin provided by the American company Mattermost, offering powerful feature extensions and tight integration with servers and network/desktop applications. Versions 11.5, 11.1.5, 10.13.11, and 11.3.4.0 of Mattermost Plugins contain security vulnerabilities. These...

PT-2026-41654

Mattermost Desktop App versions =6.1 6.0.1 5.4.13.0 fail to prevent server-rendered content from closing an underlying application view in the Mattermost Desktop App which allows a malicious server or plugin to crash the desktop client via invoking window.close in the renderer context, leading to...

Denial Of Service (DoS)

Mattermost is vulnerable to Denial of Service DoS. The vulnerability is due to improper handling of excessively long passwords during authentication, which allows an attacker to consume excessive CPU and memory resources by submitting login attempts with multi-megabyte passwords...

GHSA-HW87-6JCQ-9F8Q Mattermost doesn't enforce the PostEditTimeLimit on non-message post fields

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13 fail to enforce the PostEditTimeLimit on non-message post fields which allows an authenticated user to modify post file attachments, props, and pin status after the edit window has expired via the post patch and update API endpoints...

Mattermost doesn't enforce the PostEditTimeLimit on non-message post fields

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13 fail to enforce the PostEditTimeLimit on non-message post fields which allows an authenticated user to modify post file attachments, props, and pin status after the edit window has expired via the post patch and update API endpoints...

GHSA-J76W-P754-G2W7 Mattermost doesn't validate the response body of proxied images

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13, 11.4.x = 11.4.3 fail to validate the response body of proxied images, which allows a remote attacker to enact client-side DoS via an SVG file served from an attacker-controlled origin under a non-SVG Content-Type header e.g. image/png...

CVE-2026-33813 vulnerabilities

Vulnerabilities for packages: gitea, rclone, ollama, mattermost, bento, seaweedfs, kubescape, pdfcpu...

CVE-2026-4054

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13, 11.4.x = 11.4.3 Fail to validate the response body of proxied images, which allows a remote attacker to enact client-side DoS via an SVG file served from an attacker-controlled origin under a non-SVG Content-Type header e.g. image/png...

CVE-2026-4053

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13 fail to enforce the PostEditTimeLimit on non-message post fields which allows an authenticated user to modify post file attachments, props, and pin status after the edit window has expired via the post patch and update API endpoints...

CVE-2026-4053

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13 fail to enforce the PostEditTimeLimit on non-message post fields which allows an authenticated user to modify post file attachments, props, and pin status after the edit window has expired via the post patch and update API endpoints...

EUVD-2026-30586

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13 fail to enforce the PostEditTimeLimit on non-message post fields which allows an authenticated user to modify post file attachments, props, and pin status after the edit window has expired via the post patch and update API endpoints...

CVE-2026-4053 post edit time limit is not enforced on some post update operations

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13 fail to enforce the PostEditTimeLimit on non-message post fields which allows an authenticated user to modify post file attachments, props, and pin status after the edit window has expired via the post patch and update API endpoints...

CVE-2026-4053 post edit time limit is not enforced on some post update operations

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13 fail to enforce the PostEditTimeLimit on non-message post fields which allows an authenticated user to modify post file attachments, props, and pin status after the edit window has expired via the post patch and update API endpoints...

EUVD-2026-30590

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13, 11.4.x = 11.4.3 Fail to validate the response body of proxied images, which allows a remote attacker to enact client-side DoS via an SVG file served from an attacker-controlled origin under a non-SVG Content-Type header e.g. image/png...

CVE-2026-4054 SVG content served through Mattermost image proxy despite Content-Type restrictions causes client-side denial of service

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13, 11.4.x = 11.4.3 Fail to validate the response body of proxied images, which allows a remote attacker to enact client-side DoS via an SVG file served from an attacker-controlled origin under a non-SVG Content-Type header e.g. image/png...

CVE-2026-4054

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13, 11.4.x = 11.4.3 Fail to validate the response body of proxied images, which allows a remote attacker to enact client-side DoS via an SVG file served from an attacker-controlled origin under a non-SVG Content-Type header e.g. image/png...

CVE-2026-4054 SVG content served through Mattermost image proxy despite Content-Type restrictions causes client-side denial of service

Mattermost versions 11.5.x = 11.5.1, 10.11.x = 10.11.13, 11.4.x = 11.4.3 Fail to validate the response body of proxied images, which allows a remote attacker to enact client-side DoS via an SVG file served from an attacker-controlled origin under a non-SVG Content-Type header e.g. image/png...